Wallace Rockhole (Northern Territory) – Aluminium
2010/11: Wallace Rockhole Aluminium 0.8mg/L
2013/14: Wallace Rockhole Aluminium 0.72mg/L
According to the ADWG, no health guideline has been adopted for Aluminium, but that the issue is still open to review. Aluminium can come from natural geological sources or from the use of aluminium salts as coagulants in water treatment plants. According to the ADWG “A well-operated water filtration plant (even using aluminium as a flocculant) can achieve aluminium concentrations in the finished water of less than 0.1 mg/L.
The most common form of aluminium in water treatment plants is Aluminium Sulfate (Alum). Alum can be supplied as a bulk liquid or in granular form. It is used at water treatment plants as a coagulant to remove turbidity, microorganisms, organic matter and inorganic chemicals. If water is particularly dirty an Alum dose of as high as 500mg/L could occur. There is also concern that other metals may also exist in refined alum.
While the ADWG mentions that there is considerable evidence that Aluminium is neurotoxic and can pass the gut barrier to accumulate in the blood, leading to a condition called encephalopathy (dialysis dementia) and that Aluminium has been associated with Parkinsonism dementia and amyotrophic lateral sclerosis, the NHMRC, whilst also acknowledging studies which have linked Aluminium with Alzheimer disease, has not granted Aluminium a NOEL (No Observable Effect Level) due to insufficient and contradictory data. Without a NOEL, a health guideline cannot be established. The NHMRC has also stated that if new information comes to hand, a health guideline may be established in the future.
In communication with Aluminium expert Dr Chris Exley (Professor in Bioinorganic Chemistry
The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire UK) in March 2013 regarding high levels of Aluminium detected in the South Western Victorian town of Hamilton
“It is my opinion that any value above 0.5 mg/L is totally unacceptable and a potential health risk. Where such values are maintained over days, weeks or even months, as indeed is indicated by the data you sent to me, these represent a significant health risk to all consumers. While consumers may not experience any short term health effects the result of longer term exposure to elevated levels of aluminium in potable waters may be a significant increase in the body burden of aluminium in these individuals. This artificially increased body burden will not return to ‘normal’ levels when the Al content of the potable water returns to normal but will act as a new platform level from which the Al body burden will continue to increase with age.
Wallace Rockhole (Northern Territory) – Turbidity
2010/11: Wallace Rockhole Turbidity 36.7NTU
2013/14: Wallace Rockhole Turbidity 25.7NTU
Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.
Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap
Wallace Rockhole (Northern Territory) – Chromium
2016/17 – Wallace Rockhole (Northern Territory) – Chromium 0.06mg/L
2020/21 – Wallace Rockhole (Northern Territory) – Chromium 0.05mg/L
2021/22 – Wallace Rockhole (Northern Territory) – Chromium 0.04mg/L
GUIDELINE
Based on health considerations, the concentration of hexavalent chromium (Cr(VI)) in
drinking water should not exceed 0.05 mg/L. If the concentration of total chromium exceeds
this value then a separate analysis for hexavalent chromium should be undertaken.
GENERAL DESCRIPTION
Chromium is present in the environment in the trivalent (Cr(III)) and hexavalent (Cr(VI)) states.
Trivalent chromium is the most common naturally occurring state. Most soils and rocks contain small
amounts of chromium oxide, and weathering, oxidation and bacterial action convert this insoluble
compound into soluble Cr(III) salts.
Trivalent chromium salts are used in leather tanning, manufacture of catalysts, paint pigments, fungicides,
and ceramic and glass manufacture.
Trivalent chromium is an essential trace element for humans, with food being the major source of intake.
Hexavalent chromium occurs infrequently in nature. Its presence in water is generally the result of
industrial and domestic chromium waste discharges. Hexavalent chromium compounds are used in the
metallurgical industry for chrome alloy and chrome metal production, and in the chemical industry as
oxidising agents.
Hexavalent chromium is not considered to be an essential nutrient and harmful effects due to chromium
have been attributed to this form.
Total chromium concentrations in drinking water are usually less than 0.005 mg/L although
concentrations between 0.06 mg/L to 0.12 mg/L have been reported overseas.
TYPICAL VALUES IN AUSTRALIAN DRINKING WATER
In major Australian reticulated supplies concentrations of total chromium range up to 0.03 mg/L,
with typical concentrations usually less than 0.005 mg/L.
Wallace Rockhole – Northern Territory – Selenium
2008/2009: Wallace Rockhole Selenium 0.003mg/L (95th percentile)
2009/2010: Wallace Rockhole Selenium 0.004mg/L (max)
2010/2011: Wallace Rockhole Selenium 0.003mg/L (max)
2013/2014: Wallace Rockhole Selenium 0.004mg/L (95% percentile)
2015/2016: Wallace Rockhole Selenium 0.004mg/L (95th percentile)
Based on health considerations, the concentration of selenium in drinking water should not exceed 0.004 mg/L (2011-2025 guideline 0.01mg/L). “General description Selenium (Se) and selenium salts are widespread in the environment. Selenium is released from natural and human-made sources (such as the burning of coal). Selenium is also a by-product of the processing of sulfide ores, chiefly in the copper refining industry. The major use of selenium is in the manufacture of electronic components. It is used in several other industries, and selenium compounds are used in some insecticides, in hair shampoos as an antidandruff agent, and as a nutritional feed additive for poultry and livestock. Selenium copper alloys have also been identified as a potential replacement for lead copper alloys in plumbing products. Further information on lead replacements in plumbing products (such as selenium copper alloys) is available in Information Sheet 4.1 – Metal and metalloid chemicals leaching from plumbing products. Selenium concentrations in drinking water source waters are generally very low and depend on local geochemistry, climatic conditions (e.g. drought), pH and the presence of iron salts. Selenium in water is mainly present as inorganic compounds, predominantly selenate. Weathering of rocks and soil may result in low levels of selenium in water, which may be taken up by plants (SLR 2022). Food is the major source of intake for Australians. Cereal and grain products contribute most to intake, while fish and liver contain the highest selenium concentrations.” ADWG 2025